The present invention relates generally to information systems, storage systems and storage area networks (SANs). In information systems, it can be common to have multiple servers (also referred to as “host computers”) connected to a single storage system. These multiple servers might often issue simultaneous I/O (input/output) requests to the single storage system. When this occurs, the I/O requests from one server can easily affect the ability of the storage system to process the I/O requests from the other servers, thereby affecting performance of the other servers.
One method of addressing this issue is by implementing priority control among physical interfaces (e.g., channel ports) on storage systems, storage devices, and physical interfaces on servers. For example, priority control among physical interfaces on servers is widely used because it can prioritize at an appropriate level of granularity. Traditionally, priority control among servers has been controlled according to the operating systems (OSs) running on the servers. However, when an OS or an application running on a server is migrated to another server, priority settings on an associated storage system need to be changed because the identification information of the physical interface on the server will change. Also, when a virtual port to which a server is issuing I/O requests is migrated to from one physical interface to another physical interface on a storage system, priority settings on the storage system must be manually transferred to the new physical interface by an administrator.
Another issue that has recently risen to prominence is the amount of power consumed by servers in information facilities (e.g., data centers). One solution currently being implemented to address this issue is server consolidation through the use of virtual machine software. Virtual machine software provides multiple virtual server environments (virtual machines or VMs) on a single physical server (host computer), and enables the single server to run multiple OSs simultaneously, with each of the multiple OSs being able to have one or more separate applications run thereon. In such virtual machine environments, there is often a situation in which multiple OSs on a single server share one physical interface on the server. Thus, in such a situation, priority control among the multiple OSs can not be achieved using prior art techniques because the storage systems cannot distinguish which OS is the originator of which I/O requests since multiple OSs are using the same physical port.
Related art includes U.S. Pat. No. 7,181,607, to Ido et al., entitled “Storage Control Apparatus”; U.S. patent application Ser. No. 11/826,717, to Hara et al., filed Jul. 18, 2007, entitled Method and Apparatus for Managing Virtual Ports on Storage Systems; U.S. patent application Ser. No. 12/000,821, to Hara et al., filed Dec. 18, 2007, entitled “Avoiding Use of an Inter-Unit Network in a Storage System having Multiple Storage Control Units”; and U.S. Pat. No. 6,779,083, to Ito et al., entitled “Security for Logical Unit in Storage Subsystem”, the entire disclosures of which are incorporated herein by reference. Additional related art includes the Fibre Channel Standard and corresponding specification documents, such as are available from the InterNational Committee for Information Technology Standards (INCITS) Technical Committee T11 (e.g., t11.org). Especially, for example, documents relating to FC-FS (Fibre Channel Framing and Signaling), FC-DA (Fibre Channel Device Attach), FC-LS (Fibre Channel Link Services), FC-GS (Fibre Channel Generic Services), and FC-PH (Fibre Channel Physical and Signaling Interface) are related to this invention. For example, “Fibre Channel Framing and Signaling-3 (FC-FS-3), Project T11/1861-D Rev 0.20”, published by the American National Standards Institute, Inc. Jun. 29, 2007, the disclosure of which is incorporated herein by reference, describes the framing and signaling requirements for Fibre Channel links.